The clinical objectives of the Outpatient Department are to support all clinical investigations of the Program Project by providing outpatient treatment and follow-up care for all patients involved in the research programs. An aim of this activity is to expand the role of ambulatory care, augmenting clinic/home care, thus reducing hospital days and cost. The research objective of the core is to investigate the delayed effects of pretransplant preparative regimens on growth, development and psychological function of children. The specific aims are: 1) to determine and compare the impact of chemotherapy only and TBI preparative regimens on the incidence and time to occurrence of endocrine abnormalities and to determine if treatment with specific hormones will improve growth rates, and 2) to determine and compare the impact of chemotherapy only and TBI regimens on the incidence and time of appearance of neuropsychological abnormalities. Prospective longitudinal endocrine and psychological studies will identify patients who require treatment. This approach will increase understanding of these late effects of transplantation and determine if early treatment with hormone supplementation will result in improved growth for these children.